In a steerable-nozzle thruster, nozzle steering is controlled by actuator members, for example piston-and cylinder type actuators, which are connected at one end to the nozzle via a pivoting link connected to the wall of the diverging portion of the nozzle.
In general, the actuator member is anchored to the nozzle by means of an actuator ring which surrounds the diverging portion so as to confer the desirable stiffness and provide thermal insulation between the wall of the diverging portion and the metal anchor fitting fixed to the actuator ring.
That solution is expensive, particularly when, for reasons of limiting mass and reinforcing thermal insulation, the actuator ring is made of thermostructural composite material, e.g. a carbon/carbon (C/C) composite. In addition, it is necessary to prevent the actuator ring from moving in axial translation or in rotation. It can be prevented from moving in translation by means of a nut screwed onto the diverging portion, thereby adding another large-sized part.